A predictive model for early-warning of Septoria leaf blotch on winter wheat

Abstract

Disease-weather relationships influencing Septoria leaf blotch (SLB) preceding growth stage (GS) 31 were identified using data from 12 sites in the UK covering 8 years. Based on these relationships, an early-warning predictive model for SLB on winter wheat was formulated to predict the occurrence of a damaging epidemic (defined as disease severity of 5% or > 5% on the top three leaf layers). The final model was based on accumulated rain > 3 mm in the 80-day period preceding GS 31 (roughly from early-February to the end of April) and accumulated minimum temperature with a 0°C base in the 50-day period starting from 120 days preceding GS 31 (approximately January and February). The model was validated on an independent data set on which the prediction accuracy was influenced by cultivar resistance. Over all observations, the model had a true positive proportion of 0.61, a true negative proportion of 0.73, a sensitivity of 0.83, and a specificity of 0.18. True negative proportion increased to 0.85 for resistant cultivars and decreased to 0.50 for susceptible cultivars. Potential fungicide savings are most likely to be made with resistant cultivars, but such benefits would need to be identified with an in-depth evaluation.

Weather Conditions Associated with the Release and Dispersal of Zymoseptoria tritici Spores in the Argentine Pampas Region

“…The magnitude of these observations enhances the coincidence of our results with those obtained by other authors [4,8,18,19,23,26,27,29,30].…”

“…The results of our work also highlight the importance of solar radiation and the intensity of the rain, besides the temperature and the relative humidity, cited by other authors [4,18,19], in the release and dispersal of pycnidiospores.…”

“…If all the parts of the trap are ready, in 8 hours per day, it is possible to assemble 10 samplers. This system of monitoring guaranteed to obtain comparable observations with those obtained by other authors [4,8,18,19,23,26,27,29,30] affirming its use at experimental level. In this work, we studied the weather variables associated with release and dispersal of the conidia and ascospores of the pathogen, both in the air and in the rainwater, under Buenos Aires province conditions.…”

“…For AV identification, only two-cell, elliptical, hyaline spores of 9-16 (18) × 2.5-4.5 휇m [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] were considered; the viability of the airborne spores was determined by recording their germination and formation of secondary conidia directly on Vaseline.…”

“…Pietravalle et al [18] and Te Beest et al [19] formulated an alternative model for early-warning of a damaging epidemic, based on accumulated rain and accumulated minimum temperature in the period preceding GS31 (tillering). In addition, the first authors indicated that the early phases of the epidemic were driven by temperature, which might determine the number of disease cycles that occurred in the following winter.…”